Contraction of Cardiac Muscle Typically Requires

Question

Contraction of cardiac muscle typically requires: A)Ca⁺⁺ influx through voltage-gated Ca⁺⁺ channels to trigger a rise in cytosolic [Ca⁺⁺]. B)Ca⁺⁺ influx through voltage-gated Ca⁺⁺ channels,which is sufficient to support contraction. C)Activation of myosin light-chain kinase (MLCK). D)Phosphorylation of myosin heavy chain. E)Ca⁺⁺ influx through the Na⁺-Ca⁺⁺ antiporter.

Accepted Answer

Contraction of cardiac muscle typically requires Ca2+ influx through voltage-gated Ca2+ channels to trigger a rise in cytosolic [Ca2+]. This increase in [Ca2+] activates the actin-myosin cross-bridge cycling, leading to muscle contraction.